A useful approach when building rigs is to create more than one bone chain to accomplish different tasks. The idea behind this is to not overwhelm you with so many functions attached to one single bone, making the rig easier to understand and modify.
It is useful to separate the bone chains by their main functions to make things easier to manage: one chain that will only deform your character's mesh, one for creating Inverse Kinematics (IK) controllers, another for Forward Kinematics (FK) controllers, interface, helpers, and so on.
By creating them separately, you can make changes without breaking things in your rig. If you stack all the functions and constraints on one single chain, a little change can make a real mess. By separating them you can also make your rig more appealing and usable by defining custom shapes, colors, and hiding bones that shouldn't be touched by the animator.
You need a mesh to be deformed by the bones you'll create. Open the file 001-Chains.blend
from this book's support files. It contains a tail-like mesh so you can follow this recipe to create separate chains, producing a scorpion-like movement.
D_
, which stands for "Deformation". That's the role of these bones: they're responsible for deforming our mesh. Good names can be D_tail.1
to D_tail.8
.In Blender versions prior to 2.5, finding the name of a bone in the list displayed by the program could be a tough job, as seen in the next screenshot. Using prefixes are crucial to help you find the desired bone in a list and know its function without having to select it. With the arrival of Blender 2.5, finding a bone (or any object) by its name is much easier: just start typing in the appropriate field to narrow the selection options.
Now we're going to create the controller bone. This bone belongs to another "chain" of bones responsible for controlling the deformation ones. The controllers don't perform any mesh deformation by themselves. Although in this example this chain has just one bone for the sake of simplicity, more complex rigs can easily have dozens of them.
Tail
. The controller bones are usually named without prefixes in order to be friendlier to the animator, who will look out for Tail
instead of C_Tail
. D_tail.8
. Press Ctrl + Shift + C to bring up the Constraints menu and choose Copy Rotation. Tail
bone and rotate it. You'll see that all the bones on the deformation chain follow its rotation like a real tail, as seen in the next screenshot:By creating separate bone chains to accomplish different tasks, you end up with a very usable and organized rig, which is easy to animate and to configure, since each bone does only what is meant to do. This approach allows us to have a larger number of deformation bones to achieve softer results while still being simple to animate, having fewer bones to be controlled by the animator. This example showed how a scorpion-like tail can be controlled with only one bone, although eight bones build its structure.
The concept of separate bone chains will be discussed further throughout this book, notably when creating different chains to control arms, legs, torso, face, and eyes.
As your rig grows in complexity, you should use the bone layers that Blender offers you to manage the chains.
In some cases it is interesting to make a bone present on more than one layer. For instance, you may want to keep your main controller bones (limbs, head, torso) only on layer 1 and leave the detail controllers (facial expressions, fingers, eyes) on layer 2. But there are other bones which act only to enable and disable features of your rig, such as the ability to stretch limbs or switch between Inverse and Forward Kinematics (more about this in the recipe Making an IK-FK switcher).
These "general rig properties" should be present on both layers 1 and 2. To accomplish that, select the desired bone, press M to bring up the layer selection menu, hold Shift, and click on all the layers that you want those bones to belong to.
And always remember to use prefixes for your chains in order to find what you want quicker. You can use D_
for deformation bones, IK_
for Inverse Kinematics bones, FK_
for Forward Kinematics chains, T_
for target bones, M_
for mechanism, and so on. There's more on these uses in later recipes.
Chapter 3: Controlling the pupils
Chapter 4: Creating the jaw controller
Chapter 5: Controlling fingers
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